Electrically operable valves typically include an electric motor that drives a screw via a gear, usually a reducing gear. In some cases, the electric motor drives the screw directly, without the presence of a gear. The screw is threadingly engaged within a nut that is fixed, i.e. prevented from turning around the screw. Therefore, turning the screw moves the nut. When the nut reaches the end of the valve closing (forward) stroke, the nut presses a valve seal, typically made of silicon, against a lip of a valve body, thereby closing the valve.
However, when the seal is pressed against the lip, the electric motor may not have enough force to release the seal from the valve body lip. One solution to this problem is to increase the power of the electric motor. However, such a motor is more expensive; consumes more power; and typically has larger dimensions, whereby the valve would be larger.
It is the object of the present invention to provide a valve that significantly reduces or overcomes the aforementioned disadvantages. It is a further object of the present invention to provide a valve that enables load-free rotation starting of the thread in both directions, i.e., in a closing direction and in an opening direction.